It seems like magic when some new gadget seems to know what we want before we know ourselves. But why do some designs feel intrinsically good, and why do some designs last forever, while others disappear? User-Friendly guides readers through the hidden rules governing how design shapes our behavior told through fascinating stories such as what the nuclear accident at Three Mile Island reveals about the logic of the smartphone; how the pressures of the Great Depression and World War II created our faith in social progress through better product design; and how a failed vision for Disney World yielded a new paradigm for the designed experience.